The Mirage M1s are flat down to 30Hz and roll off to down 6dB at 25Hz, which is very respectable low base performance. If the GAS is getting too hot and regularly shutting down, then there is probably something malfunctioning in the amp. I say this assuming you are not listening at 110dB.
The 2006 Stereophile review with measurements.
The 2006 Stereophile review with measurements.